Strapping machines, which include strapping heads, are in widespread use for applying straps of thermoplastic material, such as, for example, polyester or polypropylene, in tensioned loops around packages. Typically, a strapping head of a strapping machine draws portions of a strap of such material of an indeterminate length into the strapping machine and feeds the strap around a package by means of a strap chute, whereupon the strapping head tensions the strap in a tensioned loop around the package, welds the strap in the tensioned loop state, and severs the strap forming the tensioned loop from the residual portions of the strap disposed upstream of the tensioned loop. Well known models of such strapping machines having such strapping heads are available commercially from Signode Industry Packaging Systems (a division of Illinois Tool Works Inc.) of Glenview, Ill. under its SIGNODE.TM. trademark, as exemplified by means of SIGNODE.TM. SPIRIT.TM. strapping machines.
Typically, the strapping head draws portions of the strap forwardly into the strapping machine when feeding the strap around the package and draws portions of the strap backwardly past the strapping head and in the direction away from the strapping machine when tensioning the strap. Commonly, a strap accumulator is used to accumulate portions of the strap drawn from a strap dispenser before portions of the strap are drawn by means of the strapping head into the strapping machine from the strap accumulator, and to accumulate portions of the strap drawn from the strapping machine back to the strap accumulator.
A strap accumulator, which may also be called a stretch-out box, is exemplified in Bader, Jr., U.S. Pat. No. 4,651,944. Other strap accumulators or similar devices are disclosed in Noguchi U.S. Pat. No. 3,946,921 and Brenneisen U.S. Pat. No. 3,137,426.
There has been a need, to which this invention is addressed, for improvements in strap dispensing and accumulating apparatus, which may be advantageously combined with a strapping machine within a strapping system.